1. Field of the Invention
The present invention relates to a vehicle seat having a function of transferring an impact load, input from a side portion of a vehicle, to an inner area of a vehicle body in the width direction.
2. Description of the Related Art
For example, Japanese Unexamined Patent Application, First Publication No. 2000-103275 discloses a technique of transferring an impact load, input from a side portion of a vehicle in the event of a collision or the like, to the inside of a vehicle body in the width direction through a seat.
In the vehicle seat, a seatback frame is formed in a rectangular frame shape, and a load transfer block is attached to a side frame portion near the outside in the vehicle width direction so as to protrude outward in the seat width direction and transfer an impact load input from a center pillar or the like of a vehicle body side portion to the seatback frame. Further, lower portions of left and right side frame portions of the seatback frame are connected to each other through a lower frame portion extending in the vehicle width direction, and an extension end extending downward in relation to the lower frame portion in the side frame portion is connected to a rear end of a cushion frame through a tilting shaft so as to be tiltable.
Accordingly, in the vehicle seat, when the vehicle body side portion is deformed by the input of the impact load, the vehicle body side portion comes into contact with the load transfer block, and the impact load is highly efficiently transferred to the inside of the vehicle body in the width direction through the lower frame portion and the outer side frame portion in the vehicle width direction.
However, in existing vehicle seats, the lower extension end of the side frame portion of the seatback frame is connected to the rear end of the cushion frame through the tilting shaft. For this reason, the lower frame portion used as a main load transfer path of the lower side of the seatback frame in the event of the impact load needs to be disposed to be deviated upward from the lower end of the seatback frame in order to prevent an interference with the tilting shaft. For this reason, in the case of the existing vehicle seat, the impact load input to the outer side frame portion in the vehicle width direction may not be highly efficiently transferred to the inside in the vehicle width direction in the lower area of the seatback frame at the same height as that of the tilting shaft.
Therefore, it is a first object of the invention to provide a vehicle seat capable of highly efficiently transferring an impact load to the inside in the vehicle width direction at the lower area of the seatback frame.
Further, particularly, when a driving motor for adjusting the tilting angle of the seatback frame needs to be assembled to the lower area of the seatback, the lower frame portion needs to be disposed to be deviated further upward in order to prevent the lower frame portion from interfering with the driving motor.
For this reason, in the case of the existing vehicle seat, the impact load input to the outer side frame portion in the vehicle width direction may not be highly efficiently transferred to the sufficiently low position of the seatback frame in the vehicle width direction.
Therefore, it is a second object of the invention to provide a vehicle seat capable of highly efficiently transferring an impact load to the inside in the vehicle width direction at the lower area of the seatback frame while compactly assembling the driving motor for adjusting the tilting angle of the seatback frame to the lower area of the seatback frame.